Perhaps the most notable feature of the howler monkey is the loud noise they make at dawn or dusk. This howl can be heard up to 3 miles away and is thought to be used by males for territory protection and mate guarding. Male howler monkeys have large throats and a specialized vocal chamber that helps them to make their loud calls. They are the biggest of all the New World monkeys, averaging 2.5 feet tall. Unlike Old World monkeys, howlers have a short snout with wide, side-opening nostrils. Howlers also have a prehensile tail that they use to grab fruit and hold onto branches.

Diet
Howler monkeys are folivores, meaning that they eat leaves. They are the only folivores of the New World monkeys, with leaves making up to 76% of their diet. They also enjoy figs and other fruit and will occasionally eat flowers and buds.

Reproduction & Lifespan
Sexual maturity is achieved at 5 years by males, and at 3 to 4 years for females. But often the young animals lack the social maturity to mate for several more years. Gestation is 180 to 194 days and usually results in a single birth.

The lifespan of a howler monkey is estimated at 16 years.

Fantastic FactMan’s Best Friend
Despite its loud vocalizations, the black howler monkey is commonly kept as a pet in contemporary Argentina. It is thought that this breed is kept more often than others due to its gentle nature and limited activity.